This is not a quadratic but a polynomial of the fourth degree (with at most 4 solutions).
I believe it is quite hard to factorize and/or solve fourth degree polynomials ?
So It must factor into two quadratics
since the lead term has coeffient 1 we can write the two quadratics as
Now we multiply out the left hand side to get
This give the system of equations that is hard to solve and requires alot of trial and error.
Now comes the hard work solving this system of equations.
If then if we plug into the 2nd equation
this gives two choices for a and m
The correct choice is they both check in equation 3.
Now plugging back into the equation from the beginning we get
It's impossible to factor quartics... just kidding, but I can't offer you a better method than guess and check, I mean I could, but I don't think it's any better, so....
Quartics can be factored into two quadractics (provided they have real coefficients)
Now I start playing around with stuff, we need a and a
Well it looks like and will do the job
Now the final number is -4, so our choices consist of 1,2,4 with necessary signs out in front, just running through those, again I swear this is all guess and check and it's not necessarily quick, you'll get 2 and -2
There are formulas and things you can look up and use, but this question comes up so rarely for me that I have to stumble through it. It's not an efficient way of doing it.